PCAP_COMPILE(3PCAP)                                      PCAP_COMPILE(3PCAP)

NAME         top

       pcap_compile - compile a filter expression

SYNOPSIS         top

       #include <pcap/pcap.h>

       int pcap_compile(pcap_t *p, struct bpf_program *fp,
               const char *str, int optimize, bpf_u_int32 netmask);

DESCRIPTION         top

       pcap_compile() is used to compile the string str into a filter
       program.  See pcap-filter(7) for the syntax of that string.  program
       is a pointer to a bpf_program struct and is filled in by
       pcap_compile().  optimize controls whether optimization on the
       resulting code is performed.  netmask specifies the IPv4 netmask of
       the network on which packets are being captured; it is used only when
       checking for IPv4 broadcast addresses in the filter program.  If the
       netmask of the network on which packets are being captured isn't
       known to the program, or if packets are being captured on the Linux
       "any" pseudo-interface that can capture on more than one network, a
       value of PCAP_NETMASK_UNKNOWN can be supplied; tests for IPv4
       broadcast addresses will fail to compile, but all other tests in the
       filter program will be OK.

       NOTE: in libpcap 1.8.0 and later, pcap_compile() can be used in
       multiple threads within a single process.  However, in earlier
       versions of libpcap, it is not safe to use pcap_compile() in multiple
       threads in a single process without some form of mutual exclusion
       allowing only one thread to call it at any given time.

RETURN VALUE         top

       pcap_compile() returns 0 on success and -1 on failure.  If -1 is
       returned, pcap_geterr() or pcap_perror() may be called with p as an
       argument to fetch or display the error text.

SEE ALSO         top

       pcap(3PCAP), pcap_setfilter(3PCAP), pcap_freecode(3PCAP),
       pcap_geterr(3PCAP), pcap-filter(7)

COLOPHON         top

       This page is part of the libpcap (packet capture library) project.
       Information about the project can be found at 
       ⟨⟩.  If you have a bug report for this manual
       page, see ⟨⟩.  This page was obtained
       from the project's upstream Git repository
       ⟨⟩ on 2018-02-02.
       (At that time, the date of the most recent commit that was found in
       the repository was 2018-01-31.)  If you discover any rendering prob‐
       lems in this HTML version of the page, or you believe there is a bet‐
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                                7 April 2014             PCAP_COMPILE(3PCAP)